Transmission fluids



3,250,716 TRANSMISSION FLUIDS Thomas J. Akers, East Alton, Ill., assignor to Shell Oil Company, New York, N.Y., a corporation of 'Delaware No Drawing. Filed May 3, 1963, Ser. No. 277,727 5 Claims. (Cl. 252-75) This invention relates to improved transmission fluids and more particularly to new and improved petroleum base transmission fluids possessing excellent performance properties over wide temperature ranges in various transmission systems.

Current transmission systems require transmission fluids that function over wide temperature'ranges of from about minus sixty-five (65 F.) to such elevated temperatures as 350 F. and higher. Not only must such fluids provide good lubricity over this temperature range but they must prevent formation of contaminates and damage to both metal and non-metal parts of such equipment caused by wear, corrosion and pitting of the metal surfacesand deterioration and swelling of rubber and other non-metallic parts of such systems.

In order to provide proper fluidity and other desired properties of said types of transmission fluids, various base fluids are used such as synthetics of the sebacate ester or the organic phosphorus ester type or light mineral .oils compounded with various polymeric type thickeners known in the art as viscosity index (VI) improvers and include polymeric olefins, polymers of esters of an acrylic acid and long chain alkanols and the like. Generally it has been found that synthetic base fluids are not desirable because of their tendency to damage non-metals, cause corrosion and their incompatibility with VI improvers, and also they are costly. Mineral oil base transmission fluids although less costly, also possess serious shortcomings such as their tendency to cause swelling of rubber parts, foaming, requirement of excessive amounts of VI improvers in order to attain proper temperature-viscosity requirements and the like.

It has now been discovered that by blending two particular mineral oil fractions in definite proportions, that such a base blend provides excellent Wide temperatureviscosity requirements for transmission fluids, inhibits foaming and rubber swelling and functions as an improved solvent and activator for additives, e.g., VI improvers and detergents generally incorporated into such fluids in amounts of from 1% to by weight.

The mineral oil base blend, which functions in the unusual desired manner mentioned above comprises a mixture of two highly solvent refined mineral oils, fraction (I) being a medium viscosity index (30-50 VI) mineral oil in the viscosity range of from 50 to 150 SUS at 100 F. and an aromatic content between 5 and and the other mineral oil fraction (II) being a high viscosity in dex oil having a viscosity index above 85, preferably between 110 and 150 VI, an aromatic content between 15 and 30% and a viscosity range of from 80 to 250 SUS at 100 F.

By highly solvent refined oils is meant that both oil fractions (I) and (II) have been solvent refined by such United States Patent 0 means as propane or methylethyl ketone dewaxing, followed by solvent reactment using as solvents a phenol, sulfur dioxide or furfurol at temperatures of from 100 to 150 F. and a solvent to oil ratio of from 2:1 to 5:1, respectively.

The two oil fractions can be blended in amounts ranging from 15 to 85% of the medium VI oil fraction (I) to 85% to 15% of the high VI oil fraction (H).

The two oil fractions and their required properties are 20 illustrated by the examples shown in Table I.

3,250,716 Patented May 10, 1966 TABLE I.T1'-IE INSPECTION PROPERTIES OF EXPERI- MENTAL TRANSMISSION FLUID BASE STOCKS IIA II-B II-C I-A HVI 100 HVI 56 HVI 43 MVI 100 Properties SUS at SUS at SUS at SUS at 100 F 100 F. 100 F 100 F.

Gravity, API at 60 F- 32.0 36. 2 39.1 28. 3 Vis. S.S.U. at 210 F 41. 4 34. 9 31.6 38.8 Viscosity Index 89 88 90 44 Specific Dispersion. 109 101 103 103 Aniline Cloud Point, 210 203 194 190 Flash Point, F 395 335 310 340 Pour Point, F +10 +5 +10 30 Sulfur, percent wt 0. 08 0. 00 0. 00 0. 10 Nitrogen, p.p.m 27

MASS SPECTROMETRIC ANALYSIS OF BASE STOCKS Compound Type I-A II-A Normal Alkanes 0.5 7. Total Allranes 1. 0 19. Noncondensed Cycloalkanes 44. 1 39. Condensed Cyoloalkanes 38. 4 l9. Monoaromatics 10. 5 11. Diaromatics 2. 9 5. Triaromatics 1. 2 2. Tetraand Pentaaromaties 0. 2 0. Diaromatic Sulfur Compounds. 0. 3 0. Triaromatic Sulfur Compounds 0.4 0. Other Sulfur Compounds 1. 0 0. VI 44 89 B Molecular sieve determination.

Base blends of this invention are shown by the following illustrative examples: Example A=70% I-A and 30% II-B, Example B=35% LA and 65% II-A, Example C=85% I-A and 15% II-C.

Among the additive agents used for improving transmission fluids are the so-called pour point depressing VI improvers such as oil-soluble polymers of esters of an acrylic acid and a C alkanol. Preferred are the polymeric esters of methacrylic acid and monohydric alcohols having 8 to 18 carbon atoms in the molecular Weight range of from 5000 to 20,000 and fully described in US. Patents 2,407,954 and 2,710,842. A C alkylmethacrylate ester (X) in the molecular weight range of 10,000l5,000 which is particularly preferred for incorporating into oil blends of the present invention has the following properties:

Sp. gr., 60 F./60 F. 0.096 Lbs/gal. 754 Flash point, C.O.C., F. 400 Pour point, ASTM, F. 25 Viscosity, cs./ F. 9,400 Viscosity, SUS/100 F. 43,000 Viscosity, cs./2l0 F. 800 Color, ASTM 3 Neut. No. 0.2

The detergent class which is particularly compatible with the base blend of this invention are the non-ash forming nitrogen-containing polymeric detergents of copolymers of monomers having polymerized linkages and containing nitrogen-containing groups which may be amino or amido groups. They may be derived from polymerizable monomers containing primary, secondary or tertiary (the latter two are preferred) amino nitrogen, including heterocyclic amino or amido nitrogen-containing substances, having an ethylenically unsaturated polymerizable group. These detergent polymers may be obtained by polymerizing vinyl substituted heterocyclic nitrogen-containing substances such 'as vinyl pyridine, vinyl py-rrolidone or vinyl arylamines such as paraaminostyrene, and the like. The preferred polymeric amino or amido compounds are those containing tertiary 3 amine groups and particularly those containing heterocyclic amino groups such as obtained by copolymerizing a polymerizable unsaturated material free of heterocyclic nitrogen-containing radicals such as are described .in British patent specification 760,544 and U.S. Patents 2,839,512 and 2,889,282. The copolymers include: copolymer of stearyl methacrylate, and 2-methyl-5- vinyl pyridine; copolymer of stearyl methacrylate, lauryl methacrylateand 2-methyl-5-viny1 pyridine; and those which contain additional C alkyl methacrylates in the polymer, such as copolymers of stearyl methacrylates, lauryl methacrylate, methyl methacrylate and Z-methyl-S-vinyl pyridine; and similar copolymers in which the methyl methacrylate is replaced by butyl methacrylate and the Z-methyl-S-vinyl pyridine is replaced by 5-ethyl-2-vinyl pyridine; or copolymer of lauryl methacrylate and N- vinyl pyrrolidone or similar copolyrners as described in the British Patent 808,664, and mixtures thereof. Acrylate-vinyl pyrrolidone copolymers are illustrated by copolymers of N-vinyl pyrrolidone and lauryl methacrylate of varying molecular Weights. Other suitable polymeric amines are copolymers of lauryl methacrylate and diethylaminoethylmethacrylate (note U.S. Patent 2,737,- 496). These copolymers range in molecular Weight from 300,000 to 1,000,000, preferably from 400,000 to 800,000 as determined by the light scattering method.

Particularly preferred detergent polymers are Acryloid 917 and 966 copolymers of N-vinyl pyrrolidone and lauryl methacrylate in the molecular weight range of The base blends of the present invention produce su 'perior low-and-high-temperature viscosities (than are obtainable with either base stock separately, and because of their greater solvency power less of the VI improver and/or detergent polymer is required. The finished product possesses better volatility and causes no rubber swelling or foaming.

The novel improvements which are attained with transmission oil blends of the present invention is illustrated by the data presented in Tables 11 and HI.

TABLE IL-EFFECT OF BASE BLENDS OF PRESENT IN- VENTION ON FLOW CHARACTERISTICS OF AUTOMATIC TRANSMISSION FLUIDS TO MEET TYPE A, SUFFIX B REQUIREMENTS Methacrylate Viscosity at Polymer (X) Brookfield Base Stock 100 F., SUS to Approx. 50 Viscosity,

SUS at cp.at, 40F. 210 F.

(1) LA 80 5. 7 21, 000 (2) IA 100 4. 0 41, 000 (3)-IIB 80 6. 6 93, 000 II-B 100 4. 0 45, 000 (.5) Example 80 5. 7 16, 000 (6) Example 13. 80 6. 2 14, 000 (7) Example 0 80 5.7 ,0

TABLE III.EFFECT OF VT IMPROVER ON LOW TEMPERA- TURE FLOW CHARACTERISTICS OF BASE STOCKS 1 Ratio 01 reduced polymer viscosity at 210 F. to reduced polymer viscosity at 40 F.

Other additives which can be incorporated into the base blends of the present invention include polyvalent metal petroleum sulfonates, or dialkyldithiophosphates, or dialkyldithiocarbamates, or metal salts of fatty acids such as Zn, Ca, Ba or Mg petroleum sulfonate, dicyclohexyl dithiophosphate, dihexyldithiophosphate, dibutyldithiocarl'iarnate, oleate; organic amines, e.g., phenyl-u-naphthyl amine; alkyl phenols, e.g., 2,6-ditert.butyl-'4-methyl phenol, methylene bisphenol, e;g., 4,4-methylene bis(2,6- ditert.butyl phenol), bis(sec.butylaminophenyl) ether and mixtures thereof. Preferred are zinc and barium dialkyl dithiophosphaite and Cd, Ba or Zn petroleum sulfonate, carbonated basic barium and zinc salt of P S -olefin reaction product and the like. i

The amount of additive used in compositions of the present invention can vary irom 0.1% to 10% by weight.

Mineral oil blends of the present invention can be also used for various industrial lubrication purposes such as base stocks for engine lubricants, cutting fluids, rolling lubricants and the like.

I claim as myinvention:

1. An improved transmission fluid consisting essentially of a mixture of twomineral oil fraction of: (I) 30-50 VI mineral oil in the viscosity range of from 50 to 150 SUS at 100 F. and an aromatic content of 5-15% and (II) -150 VI mineral oil in the viscosity range of from 80 to 250 SUS at 100 F. and an aromatic content of 1530% fractions (I) and (11) being solvent refined and blended in proportions of 1585% to -15% respeotively and having incorporated therein from about 1% to about 10% of a copolymer of C alkyl methacrylate ester having a molecular weight range of from 10,000 to 15,000.

2. An improved transmission fluid consisting essentially of a mixture of two mineral oil fractions of: (I) 30-50 VI mineral oil, 50-100 SUS at F. and an aromatic content of 5-15% and (II) a 100-150 VI mineral oil, 80-150 SUS at. 100 F. and an aromatic content of 15-30%, fractions (1) and (11) being solvent refined and blended in proportions of (I):(II) of 15- 85% and 85-15% respectively and having incorporated therein from about 1% to about 10% of a copolymer of octyl and lauryl methacrylates in the molecular weight range of from 10,000 to 15,000.

3. The transmission fluid of claim 2 containing from about 1% to about 10% of carbonated basic 'Ba and Zn salt of P S -olefin reaction product.

4. The transmission fluid of claim 2 containing from about 1% to about 10% of a copolymer of N-vinyl pyrrolidone and a C alkyl methacrylate in the molecular weight range from 400,000 to 500,000.

5. The transmission fluid of claim 2 containing from about 1% to about 10% each of carbonated basic Ba and Zn salt of P S -olefinreaction product and copolymer of N-vinyl pyrrolidone and lauryl methacrylate having a molecular weight of 400,000-500,000.

References Cited by the Examiner UNITED STATES PATENTS OTHER REFERENCES Kalichevsky, Petroleum Refining with Chemicals, Elsevier Publishing Company, 1956, New York, N.Y. (pp.

- 544, 545 relied on).

DANIEL E. WYMAN, Primary Examiner.

C. O. THOMAS, I. VAUGHN, Assistan t'Examiners. 

2. AN IMPROVED TRANSMISSION FLUID CONSISTING ESSENTIALLY OF A MIXTURE OF TWO MINERAL OIL FRACTIONS OF: (I) 30-50 VI MINERAL OIL, 50-100 SUS AT 100*F. AND AN AROMATIC CONTENT OF 5-15% AND (II) A 100-150 VI MINERAL OIL, 80-150 SUS AT 100*F. AND AN AROMATIC CONTENT OF 15-30%, FRACTIONS (I) AND (II) BEING SOLVENT REFINED AND BLENDED IN PROPORTIONS OF (I): (II) OF 1585% AND 85-15% RESPECTIVELY AND HAVING INCORPORATED THEREIN FROM ABOUT 1% TO ABOUT 10% OF A COPOLYMER OF OCTYL AND LAURYL METHACRYLATES IN THE MOLECULAR WEIGHT RANGE OF FROM 10,000 TO 15,000.
 3. THE TRANSMISSION FLUID OF CLAIM 2 CONTAINING FROM ABOUT 1% TO ABOUT 10% OF CARBONATE BASIC BA AND ZN SALT OF P2S5-OLEFIN REACTION PRODUCT. 